L to R: Peter Flemings, Mark Andrews and Kristopher Darnell of the University of Texas at Austin; Stephen Ramsdell and Orrin Cone, drillers with New England Boring; and John Germaine pose on Killian Court with a drilling rig that helped the researchers gather data on an experimental probe that measures soil pore pressure. Photo / Amy Adams

September 30, 2010

By Debbie LeveyCivil & Environmental Engineering

In a research project run by CEE senior research associate John Germaine this past summer, a drilling rig on the lawn of Killian Court forced an experimental probe into the underlying clay to measure pore pressure, a soil characteristic that helps determine the stability of offshore oil platforms.

“Knowing the pore pressure allows engineers to more accurately determine underwater soil strength and better design wells and offshore platforms to avoid blowouts and collapse,” Germaine said. “It would be very useful to measure in-situ pore pressures very quickly, and our new design lets us predict the equilibrium pore pressures faster than any other tool.”

With previous funding from the National Science Foundation’s Ocean Drilling Program, Germaine, Matt Chartier S.M. ‘05 and Peter Flemings of the University of Texas at Austin created a tapered probe to determine pore pressure and ground temperature. However, testing the device in the Gulf of Mexico proved difficult and expensive, with the drilling rig costing $200,000 per day. The team needed to find a place to test the new probe on land, so they could gather data at a small fraction of the cost of renting an ocean rig.

Germaine asked Joe Gifun of the Systems Engineering Group of MIT’s Department of Facilities about drilling in the well-studied Boston blue clay under the campus. “It turns out that MIT intended to study the top 20 feet to understand variations of the water table above the clay,” said Germaine. “I suggested that as long as they were drilling holes, to let me drill a deeper hole. We were able to test pore pressures from 40 feet to 170 feet down.”

“I was extremely happy with MIT for allowing us to drill in the courtyard. Instead of renting a truck and transporting everything to a distant site, we could take a sample and just walk into our laboratory,” said Germaine. “We found that we definitely need to make the probe more robust, as well as make some internal mechanical changes. Now all we need is another drilling program to test version two in the ocean.”